The present disclosure relates to a developing device that supplies an image carrier with a developer and an electrophotographic image forming apparatus including the same.
In an electrophotographic image forming apparatus, a peripheral surface of an image carrier (photosensitive drum) is irradiated with light based on image information read from an original image or image information obtained by, for example, transmission from an external apparatus such as a computer so that an electrostatic latent image is formed, which then is supplied with toner from a developing device so that a toner image is formed, after which said toner image is transferred onto a paper sheet. The paper sheet that has thus gone through transfer processing is subjected to processing for fixing the toner image and then is ejected to an exterior.
By the way, with advances toward color printing and high-speed processing, an image forming apparatus of recent years has a more complicated configuration, and in a developing device thereof, high-speed rotation of a toner stirring member is necessitated in order to achieve such high-speed processing. Particularly in a development method that employs a two-component developer containing a magnetic carrier and toner and uses a magnetic roller (toner supply roller) that carries the developer and a developing roller that carries only the toner, at an opposing portion where the developing roller and the magnetic roller are opposed to each other, by a magnetic brush formed on the magnetic roller, only the toner is carried on the developing roller, and a part of the toner remaining without being used for development is peeled off from the developing roller. This makes it likely that suspension of toner occurs in a neighborhood of the opposing portion where the developing roller and the magnetic roller are opposed to each other, and the suspending toner is deposited at a periphery of an ear cutting blade (regulation blade). When the toner thus deposited flocculates and adheres to the developing roller, there is a possibility that toner dropping occurs to cause an image failure.
As a solution to this, for example, there is known a developing device that employs a two-component developer containing a magnetic carrier and toner and uses a magnetic roller that carries the developer and a developing roller that carries only the toner, in which there are provided a toner receiving support member that is opposed to the developing roller or the magnetic roller, a toner receiving member that is disposed along a longitudinal direction of the toner receiving support member and receives toner dropping from the developing roller, and a vibration generation unit that causes the toner receiving member to vibrate.
There is also known a developing device in which at each of both end portions of a toner receiving support member in a longitudinal direction thereof, a sheet-shaped vibration adjustment member is disposed at a prescribed spacing from a toner receiving member. In the developing device of this type, the toner receiving member, when it vibrates, comes in contact with the vibration adjustment member, so that a free end of the toner receiving member vibrates in an undulating manner while being bent in an arc to cause toner deposited on a free end side of the toner receiving member to move to a fulcrum side thereof.